In beef cattle breeding programs, various selection criteria have been proposed and employed with the aim of improving traits related to carcass composition and the quality of the final product, ...meat. However, the importance of genotype by environment interaction (G×E) for such traits is still not well understood. Our objectives were: 1) to investigate the importance of G×E on ultrasound carcass traits, growth and visual scores and 2) to estimate the genetic correlation of ultrasound carcass traits with growth and visual scores taking into account the G×E in Hereford and Braford cattle. A multiple-trait reaction norm model was fitted to the field records of 37,948 animals. With the exception of postweaning average daily weight gain (ADG), the G×E can lead to important changes in the ranking of estimated breeding values of sires across environments for all traits. Thus, models that consider heterogeneity of genetic variances along an environmental gradient may be considered more appropriate for genetic evaluations of animals reared under conditions similar to the present study. Based on estimates of genetic correlation, the quality of visual scores or ADG as indicators of carcass quality assessed by ultrasonography is dependent on the production environment.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Introduction: there is a recent increase in interest in the use of medicinal and phytotherapeutic plants. Objective: to verify the effect of ethanolic extracts from different parts of fruits of two ...species of the genus Syzygium, on glucose and lipid levels in the blood, using animal models. Results: the bark extract of the seeds of S. cumini (Lamarck) Skeels proved to be effective in reducing blood glucose levels. This same extract was also effective in lowering blood cholesterol levels. The extract from the seed nuclei of S. cumini (Lamarck) Skeels and S. paniculatum (Gaertn) were effective in reducing blood triglyceride levels. Extracts from all parts of the fruits of S. cumini (Lamarck) Skeels and of the seed nuclei of S. paniculatum (Gaertn) prevented weight gain in the animals. Conclusion: in general, the seed extract of both species showed a direct influence on the parameters and characteristics under study.
Stayability (STAY) is a way to evaluate the productive longevity of females. Measuring the STAY at each cow calving allows earlier indicators of longevity to be obtained. Our objective with this ...study was to verify the association between STAY and consecutive calvings and traits potentially used as selection criteria in beef cattle, such as age at first calving (AFC), days to calving (DC), weaning weight (WW), and yearling weight (YW). Data from the Nelore, Angus/Brangus, and Hereford/Braford breeds were used. The estimation of variance components and subsequent prediction of breeding values were performed for all traits. The estimated breeding values (EBV) were used to analyse the association between STAY and the other traits. The Pearson's correlation estimated between the EBV for the intercept coefficient for STAY to consecutive calvings and those of AFC, DC, WW (direct and maternal effects), and YW was favourable and of low magnitude (<0.25) depending on the breed studied. The influence of the genetic merit of AFC on the chance of selection for STAY was favourable and relevant regardless of the intensity of selection and breed. DC and WW (maternal effect) traits were favourably influenced by the chance of selection for STAY, irrespective of breed. The WW (direct effect) did not affect the chance of selection for STAY for the Nelore and Hereford/Braford breeds and negatively influenced, but to a small extent, the Angus/Brangus breed. For YW, an increase in genetic merit affected the chances of selection for STAY, depending on the breed and selection intensity evaluated. The influence of the genetic merit for AFC, DC, and WW (maternal effect) on the chance of selection for STAY to consecutive calvings was favourable and relevant regardless of the selection intensity scenario evaluated. The WW (direct effect) did not influence the chance of selection for STAY. For the scenario with high selection intensity, the selection for YW favourably influenced the chance of selection for STAY in Angus/Brangus and Hereford/Braford breeds but not in Nelore.
The aim of this study was to evaluate the genetic variability, genetic and phenotypic associations, and genetic gains of birth (BW), weaning (WW), and yearling (YW) weights, loin muscle area (LMA), ...backfat thickness (BF), rump fat thickness (RF), scores of body structure (BS), finishing precocity (FS), and muscling (MS) in Nelore cattle. Genetic parameters were obtained through Bayesian inference using BLUPF90 programs. All studied traits showed genetic variability, with heritability ranging from 0.29 to 0.47. In all studied ages, weights presented positive genetic correlations with LMA (ranging from 0.13 to 0.53), being generally stronger in comparison with the other carcass traits analyzed (BF and RF). Similarly, weights were higher genetic associated with BS (0.47–0.92) than with FS (0.18–0.62) and MS (0.22–0.65), respectively. The BF and RF showed positive and moderate genetic associations with FS and MS (0.31–0.36). Genetic trends were significant (P < 0.05) and favorable for WW, YW, and visual scores. Selection for increasing BW, WW, YW, and LMA will result in modest or no change in BF and RF (correlated response ranging from -0.04 to 0.07 mm per generation). In this population, carcass traits must be included in the selection indexes to obtain genetic gains in carcass quality, if desired.
The objective of this work was to compare genetic evaluations of milk yield in the Gir breed, in terms of breeding values and their accuracy, using a random regression model applied to test-day ...records or the traditional model (TM) applied to estimates of 305-day milk yield, as well as to predict genetic trends for parameters of interest. A total of 10,576 first lactations, corresponding to 81,135 test-day (TD) records, were used. Rank correlations between the breeding values (EBVs) predicted with the two models were 0.96. The percentage of animals selected in common was 67 or 82%, respectively, when 1 or 5% of bulls were chosen, according to EBVs from random regression model (RRM) or TM genetic evaluations. Average gains in accuracy of 2.7, 3.0, and 2.6% were observed for all animals, cows with yield record, and bulls (sires of cows with yield record), respectively, when the RRM was used. The mean annual genetic gain for 305-day milk yield was 56 kg after 1993. However, lower increases in the average EBVs were observed for the second regression coefficient, related to persistency. The RRM applied to TD records is efficient for the genetic evaluation of milk yield in the Gir dairy breed.
Resumo: O objetivo deste trabalho foi comparar as avaliações genéticas da produção de leite na raça Gir, em termos dos valores genéticos preditos e de suas acurácias, por meio de modelo de regressão aleatória aplicado aos registros de produção de leite no dia do controle ou de modelo tradicional aplicado às estimativas de produção de leite acumulada em até 305 dias de lactação, bem como predizer tendências genéticas para parâmetros de interesse. Um total de 10.576 primeiras lactações, que correspondem a 81.135 registros de produção de leite no dia do controle (PLDC), foi utilizado. As correlações de ordem entre os valores genéticos preditos (VGP) com os dois modelos foram de 0,96. O percentual de animais em comum foi de 67 ou 82%, respectivamente, quando 1 ou 5% dos touros foram escolhidos, de acordo com os VGP das avaliações genéticas utilizando um ou outro modelo. Foram observados ganhos médios em acurácia de 2,7, 3,0 e 2,6% para todos os animais, vacas com fenótipo e touros (pais de vacas com fenótipo), respectivamente, quando o modelo de regressão aleatória (MRA) foi utilizado. O ganho genético médio anual para a produção de leite acumulada em até 305 dias de lactação foi de 56 kg após 1993. Entretanto, menores incrementos na média dos VGP foram observados para o segundo coeficiente de regressão, relacionado à persistência. O MRA aplicado às PLDC é eficiente para as avaliações genéticas da produção de leite na raça Gir Leiteiro.
Resumo: O objetivo deste trabalho foi estimar o efeito da endogamia sobre a produção de leite e sua persistência durante a lactação, em bovinos Gir leiteiro, bem como determinar o impacto de se ...considerar ou não o efeito da endogamia na avaliação genética dessa característica. Utilizaram-se 89.490 registros de produção no dia do controle, de 11.675 vacas em primeira lactação. O coeficiente e o incremento de endogamia individuais e o número equivalente de gerações completas de cada indivíduo foram computados. A depressão por endogamia foi estimada pela inclusão do efeito do incremento individual de endogamia, em um modelo de regressão aleatória. As soluções para a depressão por endogamia, de acordo com a classe de incremento individual de endogamia e a quinzena da lactação, variaram entre -1,238 e -0,135 kg, o que indica a redução da produção de leite com o aumento da endogamia. Em níveis mais elevados, a endogamia reduziu a persistência da produção de leite. A inclusão do efeito da endogamia no modelo de avaliação genética não afetou as estimativas de parâmetros genéticos e, praticamente, não alterou a predição dos valores genéticos e a classificação dos animais. Pode-se incluir o efeito da endogamia no modelo estatístico para a avaliação genética da característica produção de leite.
•Sexual dimorphism is observed in genetic parameters and environmental sensitivity.•The inclusion of sex in defining the environmental descriptor introduces bias.•However, sex-specific analysis is ...appropriate for estimating genetic parameters.
This study investigates the environmental sensitivity and sexual dimorphism in the genetic parameters of weaning weight (WW) in Nelore beef cattle. Five reaction norms models were employed to analyze the 148,131 WW records, considering different definitions of the environmental descriptor (ED). (Co)variance components and genetic parameters were separately estimated for males and females. Results reveal substantial sexual dimorphism in various parameters. Significant divergence across sexes was observed for environmental sensitivity, with males showing an increased response to favorable environments while females genetically responded better to more challenging environments. Including sex in defining the ED can inflate the estimated breeding values of sires with a higher number of male progeny records, highlighting the importance of choosing a reliable ED in analyses of traits influenced by sexual dimorphism and genotype-by-environment interaction (G × E). The observed sexual dimorphism and environmental sensitivity underscore the complexity of genetic evaluation of WW in beef cattle populations, with implications for selection strategies. The findings suggest that a sex-separated trait analysis considering G × E effects is most appropriate for genetic evaluations of WW. However, a simpler single-trait model excluding sex from the ED definition yielded a higher coincidence of selected sires with the sex-separated analysis. In conclusion, understanding sexual dimorphism and environmental sensitivity is crucial for genetic evaluations and selection decisions in beef cattle breeding programs, emphasizing the need for careful model selection and ED definition.
The physicochemical characteristics of the meat from lambs fed diets containing whole or disintegrated cottonseed, associated or not with calcium lignosulfonate (LignoCaSO3), were evaluated. Thirty ...non-castrated Dorper x Santa Inês lambs, with an average of 24.9 ± 3.6 kg and four months of age were confined for 60 days in collective stalls and distributed in a completely randomized design with six replications. After slaughter, by means of contrasts, the averages of the parameters of the semimembranous and semitendinosus muscles were analyzed. The cottonseed increased cooking loss and ash, and reduced muscle weight, water holding capacity and red intensity. The disintegration of the cottonseed reduced the shear force in diets without LignoCaSO3, increased the protein and the loss by cooking and reduced the pH in the diets with the additive. The luminosity values increased with the disintegration of the cottonseed in diets with and without LignoCaSO3. The addition of LignoCaSO3 increased the weight of the muscle, protein, ash, pH, shear strength and the intensity of red. Moisture, lipids and yellow intensity were not influenced by the diets. Even changing the physical-chemical characteristics, the cottonseed with or without LignoCaSO3 does not change the quality of the meat
The objective of this study was to evaluate the effect of use of agroindustrial co-products in the diet of lambs on the performance and nutritional quality of meat fat. Twenty lambs were distributed ...into four experimental groups: control diet (C) or diets containing cottonseed (CS), sunflower meal (SFM), and castor cake (CC). During the experimental period, data on dry matter consumption (DMC) and total weight gain (TWG) were collected. After slaughter, samples of Logissimus dorsi (LD) muscle were taken for fatty acids and cholesterol analysis. Diets C and CS provided similar characteristics of fat quality and animal performance. However, SFM and CC diets tend to form isolated groups, with different fat and performance characteristics. The SFM diet results in meat with a higher saturated fatty acids and cholesterol content. The CC diet is related to improved performance characteristics and lower cholesterol content. In conclusion, the inclusion of CC in the experimental diets provided, in the proportions used in this experiment, better characteristics of animal performance and meat fat quality.
ABSTRACT The objective of this study was to evaluate the effects of supplementing diet of lambs with agroindustrial co-products on the nutritional quality of meat fat and study the variation of fat ...quality parameters based on the type of muscle. Twenty lambs were distributed into four experimental groups and fed a control diet or diets containing cottonseed, sunflower meal, and castor cake. After 106 experimental days, the animals were slaughtered. Samples of Biceps femoris, Longissimus dorsi, Semimembranosus, and Triceps brachii muscles were taken for fatty acid and cholesterol analyses. Castor cake and sunflower meal diets produced meats with lower levels of n-6 polyunsaturated fatty acids (PUFA) compared with the control diet. Castor cake diet contributed to tissue reduction of n-3 PUFA. Lower conjugated linoleic acid concentration and polyunsaturated:saturated fatty acid (P:S) ratio and higher saturated fatty acids content and Thrombogenicity Index were observed in Longissimus dorsi meat. Of the co-products studied, although castor cake diet reduced cholesterol levels in Biceps femoris muscle, sunflower meal was identified as the preferred choice for lamb feeding, since it reduced n-6 PUFA without, however, decreasing n-3 PUFA. Longissimus dorsi meat had the lowest fat quality indexes. The more oxidative muscles, such as Biceps femoris, tend to generate meats with higher cholesterol concentrations.
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